<h1>Model</h1>
<p><b>Model</b> is a virtual geometric representation of three dimensional object. Model consist of geometric <b>Entities</b>.</p>
<p><b>Entity</b> is a collection of elements (geometric simplexes) of similar type and are divided into these types:
<ul>
<li><b>Point</b> - collection of 0D elements (node).</li>
<li><b>Line</b> - collection of 1D elements (segment).</li>
<li><b>Surface</b> - collection of 2D elements (triangle, quadrilateral).</li>
<li><b>Volume</b> - collection of 3D elements (tetrahedron, hexahedron).</li>
</ul>
Regardless of whether elements are 0D, 1D, 2D or 3D they all are represented in 3D space. For example point (node) has no dimensions. It only has a position, whereas line has one dimension (length).
</p>
<p>Each <b>entity</b> except <b>Volume</b> can have <b>geometric</b> properties assigned to complete 3D representation. These are:
<ul>
<li><b>Point</b> - volume in cubic meters.</li>
<li><b>Line</b> - cross-sectional area in meters square.</li>
<li><b>Surface</b> - thickness in meters.</li>
</ul>
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